Drying process and apparatus



June 26, 1928.

P. E. WURFFLEIN DRYING PROCESS AND APPARATUS Filed May 20. 1925 71...-., OwM w- ATTORNEYS Patented June 26, 1928.

UNITED STATES PETER E. WURFFLEIN, O1 VINELAND, NEW JERSEY DRYING PROCESS AND APPARATUS.

Application filed m so, 1925. Serial in. 31,888.

This invention relates to a process of drying materials at low temperatures and includes the improved process and the improved apparatus.

It is one of the objects of the present invention to dry materials without the use of high temperatures and excessive time and to produce a uniform drying throughout the material. It is an added advantage of the present invention that a rapid, thorough and uniform dryin is achieved without injuring delicate su stances by the use of high heat. The apparatus of the present invention also presents the advantages of simplicity of construction and reliability of operation combined with ease of charging.

Further advanta es will appear fro-m the following more etailed description of the invention.

The present invention is ap licable to the drying of any material and 15 particularly suited for the drying of such materials as leather, cloth, linoleum, ceramics, food products, such as vegetables, fruits, egg products and the like, and is also effective in drying lumber.

Drying processes used hitherto have depended for their eflicacy on the use of high temperatures, large volumes of air or a long time. The use of high temperature is disadvantageous for the drying of many substances owing to the fact that the temperature causes undesirable changes in the materials. For example, high temperature drying of hides and leather causes a very heavy shrinkage and frequently is accompanied by deterioration of the leather itself. In the case of food products such as vegetables, fruits and the like, the use of 40 high temperature or even moderate temperature with large amounts of air results in a surface dryingwhich forms a hard layer and revents the centers of the pieces of vegetab es or fruits from pro er dryin so that the product is either part y crooke if high temperature is used or has a moist center if the temperature has not been undul high. It has been particularly difficu t to d such products as pumpkins and the like w ich contain alarge amount of water. It has also been ractically im 05- sible hitherto to eflicient y dry the w ite of eggs by the prior processes.

Ceramics and clay products have also suffered in the drying processes hitherto used as the drying has been mainly on the surface and if high heat is used there is a considerable tendency to warp, particular] in large and thick ceramic products, such as the larger porcelain structures as bath tubs, wash bowls and the like which owing to their great thickness are diificult to dry and tend to crack or break easily in the kilns if not uniformly dried.

Lumber is also diflicultto dry in kilns unless great care is used as the kiln-dried products are apt to be warped or checked, and of inferior strength to the air-dried variety. The drying time is also excessive which greatly increases the cost of the lumber.

Textiles and particularly cotton cloth also present many dlfiiculties in drying owing to shrinkage.

According to the present invention, I combine warm air drying, using a large volume of warm air, with centrifugal force. I have found that products dried accordin to my process are uniformly dried throug to the center of the products as well as on the outside and are not injured by high temperatures, as I can use temperatures from to F. for most products, somewhat higher temperatures u to being permissible in t e case of ing ceramics. have also found that the rying time is very greatly reduced.

The invention will be described in reater detail in connection with the preferre form of apparatus for carrying out the process. It should be understood that the invention is not limited to the specific details set forth and particularly is not limited to the preferred type of appgratus described, but on the contrary may used in any a paratus 95 which will produce a combination 0 centrifugal force and a large volume of warm air.

The apparatus will be described in connection with accompanying drawings in which, Fig. 1 is a horizontal section through a mo double scoop drier according to m invention and Fig. 2 is a central ver ica section through the same type of drier alon the line 22. Fig: 3 is a detailed view s 0wing the deflector plate beneath the exhaust m5 openings in vertical section.

1 is a wooden floor of circular shape mounted on the shaft 2 which turns in the bearings 3 and 4 by the gear 5 which may be driven from any suitable source. Two 0 drying chambers are formed in the machine by the S-shaped partition 6 and the outside walls 7 and 8. These walls are continued outwardly in the form of two large scoops 9 and 10. Openings 11 and 12 are provided in the drying chambers at the ends opposite from their respective scoops. The drying chambers and scoops are provided with the roof 13 so that each drying chamber forms a. compartment with two openings, one the mouth of the scoop and the other openin in the floor at the opposite end of the cham er. Suitable deflector plates 14 may be placed over the openin s in the drying chambers to deflect the air ownwardly through the latter. Deflector plates 15 are laced under the openings and aid in maintaining the circulation of air. They also prevent air backing up into the chamber.

The drier is charged by opening the doors 16 and 17 and introducing the material to be dried placed on trays, shelves, or festooned over rods in the case of hides or textiles. The trays or shelves may advantageously form a unit provided with wheels so that it can be rolled into the drier and removed as a unit.

The operation of the drier is as follows:

The room in which the drier is situated is maintained at a temperature of about 80 to 120 F. and provision is made for drying the air or causing a circulation of warm, dry air in the room. The material to be dried loaded on trays, shelves and the like is rolled into the two drying chambers, the doors are closed and power is turned on. The drier rotates in the direction of the arrow and the two scoops force a constant stream of warm dry air over the material to be dried and out through the openings at the opposite ends of the drying chambers. The warm dry air combined with the centrifugal force of the rotating drier rapidly removes the moisture from the material. The speed of revolution of the drier will depend to a considerable extent on its size. I have found that a drier having an over all diameter including scoops of from .20 to 30 feet is a very convenient size for most products and a drier of such size should be rotated at a speed of about 35 revolutions per minute. Larger driers of course will be rotated somewhat slower and smaller driers somewhat faster.

I have found that the materials dried by my process are uniformly dried throughout the pieces, in the center as well as on the surface, something which has not been achieved by prior drying processes except by the use of great heat for a long time which seriously injures many of the products to be dried. I have found that the drying takes place in zones from the outside toward the center of rotation and I am of the opinion that the centrifugal force steadily drives the water toward the periphery of the drier where it is rapidly removed by the warm air. I do not know precisely what forces act on the water to remove it and do not therefore wish to limit my invention to any theoretical explanation. It is my opinion, however, that the centrifugal force acts directly on the water as if there were no centrifugal effect the drying would proceed from the portion of the chamber nearest the scoop to the portion of the chamber containing the exit opening, whereas in my drier this is not the case as pointed out above and on the contrary the drying proceeds from the periphery of the drier towards the center. Throughout the specification and claims when referring to subjecting the material to the action of centrifugal force, I wish it to be understood that the invention is notlimited to any particular theory of how the centrifugal force acts on the water.

The following specific examples are illustrations of the process of drying various products and the invention is not limited thereto but may be applied to any material to be dried.

Calf skins from the freshly killed animal or salted hides are hung in the drier and dried for about three hours at 80 to 120 F. I have found that the shrinkage is considerably less than when the drying is carried out without centrifugal force and may amount to as much as 6 inches less per skin. A further important advantage in the present process of drying hides lies in the fact that the hides may be thoroughly dried immediately after removing from the animal and washing and it is not necessary to pack them in salt for shipping. Owing to the simplicity of the apparatus it is also possible to install driers at points where the animals are slaughtered even where the volume of material to be dried is not very great. A great saving in preservatives and an improved leather result.

Ceramics are dried by placing the material on shelves or trays in the drier and I have found that most ceramic products can be dried in from 8 to 24 hours at temperatures of about 80 to 180. The length of drying and the temperature will depend of course on the nature of the article. Thus a large thick article such as a porcelain bath tub requires a longer time at a somewhat lower temperature to avoid warping, whereas on the contrary bricks may be dried rapidly at a. considerably higher temperature. Ceramics dried by my process are uniformly dried and show a minimum of cracking or breaking. The thorough drying of such thick products prevents any moisture remaining in the center which might freeze in use with a resultant crack or break. A further advantage of the process lies in the fact that the time of drying is greatly decreased and a correspondingly increased output of the ceramlcs per day is possible.

Cotton cloth is dried by my process by festooning cloth over rods in the drier and drying it for about 3 to 6 hours at about 80 to 120 F. The cloth is thoroughly and uniformly dried with little or no shrinkage. In a similar manner other textile fabrics may be dried. Wool and other cloths can be dried in a similar manner.

Vegetables, fruits and other food products can be effectively dried by spreading in trays or on shelves in the drier and drying for from 3 .to 6 hours at about 80 to 120 F. The time taken depends considerably on the water content of the vegetable an on the tenacit with which the water is held. For examp e, celery which contains from 80 to 90% of water may be dried in about 3 hours, whereas onions which may contain as high as 96% of water usually take about 4 hours. Slicing or finely divi ing the material of course reduces the time taken. The vegetables dried by my proce:s retain a maximum of their natural flavor and do not have any of the cooked flavor which is characteristic of vegetables dried at high temperatures. Moreover, the ve tables dried b my process are dried in t e center as we 1 as on the surfaces and are therefore not liable to rot in the center as in the case with high temperature dr ing without the use of centrifual force w ere the surface dries to form a ard layer which prevents the moisture from the center from escaping. Preservatives such as sulfur, sodium benzoate, etc., are therefore unnecessary.

Milk may be eflicaciously dried in my drier by causing it to flow over a considerable surface, as for example by using shallow pans with sloping sides so that the centrifugal force of the drier tends to spread the milk in the form of a fine film. Milk so dried does not have a cooked flavor and will keep indefinitely when kept dry.

Eggs may be advantageously dried by my process. It is of particular advantage in the drying of white of ye gs which has hitherto not been commerciafly practical by the ordinary' drying method owing to the coagulation of the albumen and the formation of hard horny substances. A fine powder of white of egg can be produced by my process by beating up the whites of eggs and spreading them on a coarse screen over shallow trays. As the eggs dry out they form a powder which fall; through the screen and at the end of the drying all of the whites are in the form of a fine powder which can be readily used in making pastry or other food products and can also be redissolved in cold water which is not possible with whites of eggs which have been dried at a higher temperature.

Lumber may also be dried in my drier by stackin it on spacers which ma be in the form 0 cleats on the side of t 1e drier or any other suitable method which permits an even circulation of air around the lumber to be dried. I have found that most green lumber can be dried in from 1 to 2 days at about 80 to 120 F. and the dried product possesses all of the advantages of the airdried product without entailing the months of dry! required by this process. There is practical y no warping or checking of lumer dried by my process and the time c'ompares very favorably with kiln drying while avoiding the warping and other disadvantages incident to this method.

The above examples will illustrate materials which can be dried by the present invention and it should be understood that they are illustrations only and that any other products which require drying can be dried y my process with the corresponding advanta es.

It wil be seen that the process constitutes a simple and effective method of drying materials which are injured by the use of too hi h heat and results in a product which is uni orml dried throughout its mass and is not mere y surface dried. .The preferred form of apparatus is also simple to build as the walls can be advantageously made of galvanized iron or similar available sheet metal and the apparatus is rugged and reliable and does not contain complicated moving parts. The rotation which is necessary to produce the efiect of centrifugal force is also effectively utilized to roduce the circulation of air by the provision of scoops. In the drawing the preferred form of double scooo drier is shown but it should be understood that the number of scoops can be increased or decreased at will. Thus it is possible to cons gpct single scoo driers and riers with 4 for ore scoops wit a corresponding increase in the number of drying chambers. I find that the double scoop arrangement is simple and practical and easily balanced, but it should be understood that the invention is not limited thereto. Other methods of inducing a draft of warm air may be combined with centrifugal force, such as for example fans, blowers and the like and my process is not limited to the particular apparatus described and illustrated, but any equivalent means for producing a current of warm dry air of course may be used.

The rocess has been described in connection with the use of warm dry air but it should be understood that in the drying of certain materials which tend to oxidize a warm dry inert gas may be substituted for air and my invention is not limited to the use of any particular dry gaseous medium. My invention is also not limited to the removal ofwater from materials and is applicable partition, doors in sai a vertical shaft, an S-shaped partition on said floor passing through the center, L- shaped walls connecting with said S-sha ed partition and forming therewith two a jacent chambers provided with scoops on the opposite ends, exhaust o enings in said floor at the ends of the cham iers opposite to the scoops, a roof covering said chambers and scoops, and means for rotating the shaft in the direction of the openings for the scoop mouths.

2. A drier comprising a floor mounted on a vertical shaft, an S-shaped partition on said floor passing through the center. L- shaped walls connectin with said S-shaped walls opening into the chambers formed, and forming therewith two adjacent chambers provided with CERTIFICATE ham No. 1,675,076.

PETER E.

scoops on the opposite ends, openings in said floor at the ends of the chambers opposite to the scoops, a roof covering said chambers and scoops, and means for rotating the shaft in the direction of the openings of the scoop mouths.

3. An apparatus as claimed in claim 1 having a curved deflector plate under the exhaust openings.

4. An apparatus as claimed in claim 1 having a curved deflector plate over the exhaust openings and a curved deflector under the exhaust openings.

5. A drying apparatus comprising in combination at least one rotatable drying chamber provided with an air scoop at one end, and an exhaust opening at the other end, acurved deflector plate under the exhaust openings and means for rotating the chamber.

6. A drying apparatus comprising in combination two adjacent drying chambers, an air scoop on opposite ends of the drying chambers, said scoops having opposed openings. each of said drying chambers being provided with an exhaust opening, a curved deflector plate under each of said exhaust openings, and means for rotating said chambers in the direction of the openings of said scoops.

In testimony whereof I affix my signature.

PETER E. WURFFIIEIN.

or coaaiacnou.

Granted June 26, 1928, to

WURFFLEIN.

It is hereby certified that error appears in the printed specification of 1b;

above numbered patent requiring correction as follows: word "crooked" read "cooked"; page 4, line 51, claim 5, for the word "openings read "opening"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of August, A. D. 1928.

M.l.Mnoea.

Act in: Gonmissioner of Patents.

Page 1, line 45, for tb' partition, doors in sai a vertical shaft, an S-shaped partition on said floor passing through the center, L- shaped walls connecting with said S-sha ed partition and forming therewith two a jacent chambers provided with scoops on the opposite ends, exhaust o enings in said floor at the ends of the cham iers opposite to the scoops, a roof covering said chambers and scoops, and means for rotating the shaft in the direction of the openings for the scoop mouths.

2. A drier comprising a floor mounted on a vertical shaft, an S-shaped partition on said floor passing through the center. L- shaped walls connectin with said S-shaped walls opening into the chambers formed, and forming therewith two adjacent chambers provided with CERTIFICATE ham No. 1,675,076.

PETER E.

scoops on the opposite ends, openings in said floor at the ends of the chambers opposite to the scoops, a roof covering said chambers and scoops, and means for rotating the shaft in the direction of the openings of the scoop mouths.

3. An apparatus as claimed in claim 1 having a curved deflector plate under the exhaust openings.

4. An apparatus as claimed in claim 1 having a curved deflector plate over the exhaust openings and a curved deflector under the exhaust openings.

5. A drying apparatus comprising in combination at least one rotatable drying chamber provided with an air scoop at one end, and an exhaust opening at the other end, acurved deflector plate under the exhaust openings and means for rotating the chamber.

6. A drying apparatus comprising in combination two adjacent drying chambers, an air scoop on opposite ends of the drying chambers, said scoops having opposed openings. each of said drying chambers being provided with an exhaust opening, a curved deflector plate under each of said exhaust openings, and means for rotating said chambers in the direction of the openings of said scoops.

In testimony whereof I affix my signature.

PETER E. WURFFIIEIN.

or coaaiacnou.

Granted June 26, 1928, to

WURFFLEIN.

It is hereby certified that error appears in the printed specification of 1b;

above numbered patent requiring correction as follows: word "crooked" read "cooked"; page 4, line 51, claim 5, for the word "openings read "opening"; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 21st day of August, A. D. 1928.

M.l.Mnoea.

Act in: Gonmissioner of Patents.

Page 1, line 45, for tb' 

